Film advance and metering mechanism for cameras

ABSTRACT

A camera includes a transport mechanism having a film winding lever which is reciprocally mounted for movement from a rest position for advancing film along an exposure plane. A film sensing pawl is movable between a retracted position on one side of the exposure plane and an extended postion transversing the exposure plane when intercepting a film perforation. The sensing pawl is interconnected with the transport mechanism for disabling the transport means when the sensing pawl is in its extended position. Means interconnecting the film winding lever and the sensing pawl hold the sensing pawl in its retracted position when the lever is in its rest position.

United States Patent 1 Peters [451 July 24,1973

[ FILM ADVANCE AND METERING MECHANISM FOR CAMERAS [73] Assignee: EastmanKodak Company,

Rochester, N.Y.

22 Filed: Dec. 1, 1971 211 Appl.No.:203,732

3,603,236 9/1971 Engelsmann 95/31 FL Primary Examiner-Samuel S. MatthewsAssistant ExaminerE. M. Bero AttorneyW. H. J. Kline et al.

[57] ABSTRACT A camera includes a transport mechanism having a filmwinding lever which is reciprocally mounted for movement from a restposition for advancing film along an exposure plane. A film sensing pawlis movable be tween a retracted position on one side of the exposureplane and an extended postion transversing the exposure plane whenintercepting a film perforation. The sensing pawl is interconnected withthe transport mechanism for disabling the transport means when thesensing pawl is in its extended position. Means interconnecting the filmwinding lever and the sensing pawl hold the sensing pawl in itsretracted position when the lever is in its rest position.

6 Claims, 6 Drawing Figures PAffimEuJulzalau sum 1 or z m U P A R w M HL A A T TORNE Yi PAIENIEBJ LM 3.147.494

SHEEI 2 BF 2 ALEXANDIiR m BY flip La ATTORNEYS 1. FILM ADVANCE ANDMETERING MECHANISM FOR CAMERAS CROSS-REFERENCE TO RELATED APPLICATIONSReference is made to commonly assigned, copending U.S. Pat.applicationSer. No. 203,733, entitled CAM- ERA, tiled in the names ofDavid E. Beach and Jeffrey R. Stoneham on Dec. 1, 1971 and Ser. No.203,524, entitled FILM METERING MECHANISM FOR CAM- ERAS filed in thename of David E. Beach on Dec. 1,

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to devices for metering perforated film in roll film cameras,and more particularly to such a device adapted to eliminate or reducethe risk of film movement during shutter operation.

2. Description of the Prior Art Devices for metering successive, rollfilm exposures by arresting the filmwinding mechanism in response to thesensing of perforations or. notches precut in the film at specificintervals are old'and well known in the art. Commonly assigned, U.S.Pat. application Ser. No. 203,733, entitled CAMERA, filed on Dec. 1,.1971 in the names of David E. Beach et al. shows a camera filmtransport-mechanism v including a sensing pawl which detects the arrivalof a perforation at a predetermined location to disable thetransport"ir' echanism. A shutter release lever may thenbe depressedto-first withdraw the sensing pawl from the perforation and to thenactivate the shutter mechanism to take a picture. While cameras havingsuch devices are satisfactory, the operator must depress the shutterrelease lever with sufficient force to overcome the spring force urgingthe sensing pawl into the film perforation. This may tend to causecamera vunsteadiness resulting in blurred pictures. j

To overcome theabove-mentioned problem of camera movement resultingfrornthe requiredexcessive force to overcome the spring force'on thepawl, coassigned U.S. Pat. application Ser. No. 203,524, entitled FILM,METERING MECHANISM FORCAMERAS, filed in the name of David E. Beachdiscloses an invention wherein a film sensing pawl is not removed fromthe perforation by the shutter release-lever, but instead remains in thefilm perforation until after a picture has been taken and the filmtransport mechanism has begun to advance film. The pawl is resilientlyurged against the trailing edge of a perforation by a spring during theexposure period. It has'been found that occasionally the pressure on thefilm from thesensing pawl coupled with vibrations 'in'the camera when ashutter driver is rapidly moved along its path of travel will cause filmmovement during the exposure interval.

One possible method of eliminating such film movement is to reduce thespring force on the'pawl so that there is less tendency for the 'film tomove. However, this may lead to early metering failure due to the factthat when the pawl is'removed from the perforation, the spring which hasurged the pawl against the trailing edge of the perforation is used toreturn the pawl to a ready position for detecting the presence of thenext succeeding perforation to be advanced along the exposure plane. Ifthe spring force has been reduced, the pawl may not return to its readyposition. Therefore, it

can be seen that a careful balancing of the spring force is necessary sothat the force is insufficient to cause film movement during thepicture-taking operation and yet sufficient to return the pawl to itsready position.

SUMMARY OF THE INVENTION I have found that the problems described abovecan be eliminated by leaving the pawl in a film perforation only duringthat period of time when the film is being advanced and by removing thepad from the perforation before the picture-taking operation. Thispermits the use of a relatively heavy spring for returning the pawl toits ready position without putting undue force on the film duringshutter operation, and yet eliminates the need for a large force on theshutter release lever to withdraw the pawl from the perforation duringthe picture-taking operation.

Therefore, it is an' object of the present invention to provide a filmadvancing and metering mechanism for a camera wherein a film sensingpawl moves into a film perforation to effect metering of the filmtransport mechanism and is removed from that perforation beforeoperation of the cameras shutter.

In accordance with a preferred embodiment of the present invention, acamera having a film transport and metering mechanism of the typedescribed above includes a gear reciprocally mounted on the housing formovement away from a rest position for advancing film along an exposureplane and a film sensing pawl which is movable between a retractedposition onone side of the exposure plane and an extended positiontransversing the exposure plane when intercepting one of the filmperforations. Means are provided interconnecting the film advancing gearand the sensing pawl for moving the pawl to its retracted position inresponse to return movement of the gear to its rest position.

The invention, and its objects and advantages, will become more apparentin the detailed description of the preferred embodimentpresented below.

BRIEF DESCRIPTION OF THE DRAWINGS In the detailed description of thepreferred embodiment of the'invention presented below, reference is madeto the accompanying drawings, in which:

FIG. 1 is asimplified elevational view of a portion of a camera inaccordance with the present invention wherein the camera elements arearranged ready to make an exposure; and v a FIGS. 2-6 are elevationalviews of the camera of FIG. 1 showing five sequential relative positionsof the camera elements during operation of the camera.

DESCRIPTION OF THE PREFERRED EMBODIMENT Becausecameras are well known,the present description will bedirected in particular to elementsforming part of, or cooperating more directly with, ap-

paratus in accordance withthe present invention. It is to be understoodthat camera elements not specifically shown or described may takevarious forms well known to those skilled in the art.

Referring now to FIG. 1, the camera illustrated as the preferredembodiment includes a housing 10 having a space for receiving a filmcartridge, partially shown at 12, containing roll film 14 withperforations 16 and 17 along one edge. The cartridge may be of the typeshown in the coassigned U.S. Pat. No. 3,138,081 which issued on June 23,1964 to Hubert Nerwin, and the film may be backed by paper 18. Suchcartridges include a take-up chamber, not shown, wherein film 14 iswound into a roll.

A film wind lever, for example a slide member 22, is reciprocallymounted on housingl by a pin-in-slot arrangement. The film wind levermay, of course, be of any well known configuration, such, as forexample, a rotationally mounted gear or gear sector. Slide member 22includes a rack wich a plurality of teeth 24 in meshing engagement withthe teeth of a gear sector 26 coaxially rotatable with a gear 20.Rotation of gear 20 in a counterclockwise direction as shown in FIG. 1winds f lm onto the take-up roll of cartridge 12. Gear 20 has aplurality of teeth 28 in meshing engagement with a ratchet pawl 30rotatably mounted on gear sector 26. Pawl 30 is biased by a leaf spring32 into engagement with the teeth of gear 20 so that upon movement ofslide member 22 to the left, as viewed in FIG. 1, the rotary movement ofgear sector 26 is transmitted to gear 20, thereby winding film into thecartridges take-up chamben'As slide member 22 is returned to the rightby a coil spring 34, gear 20 is prevented from rotating in a clockwisedirection by leaf spring 36 which cooperates with the teeth on a ratchetwheel 100 on a gear 38. The teeth ofgear 38 are in meshing engagementwith teeth 28 of gear 20.

A shutter release lever 40 is pivotally mounted on a stud 42 andincludes a tab 44 which may be manually depressed by a body releaselever partially shown at 46 to rotate lever 40 in a clockwise directionagainst the force of a spring 48. Movement of shutter release lever 40in a clockwise direction trips a high energy lever, not shown, tooperate the cameras shutter mechanism for effecting exposure of theportion of film 14 at the cameras exposure plane. Operation of the highenergy lever may be found described in either of the aforementionedapplications. A metering lever 96 is mounted for rotational movementabout a stud 56 and carries a metering pawl 98 urged toward an activeposition into engagement with the teeth of ratchet 100 by a spring 101to prevent rotation of gear 38. Metering lever 96 is rotated in aclockwise direction in response to similar rotation of shutter releaselever 40 byengagement of a tab 102 on the shutter release lever with atab 104 on the metering lever.

A film sensing pawl 106 is mounted for rotational and longitudinalmovement on a stud 108 on camera housing 10. Sensing pawl 106 has a pairof arms 110 and 112 which define a slot therebetween for receiving a tab114 of a retainer 116. Retainer 116 is also rotatably carried by stud108 and is urged in a clockwise direction into abutment with a tab 120on metering lever 96 by a spring 118. A spring 122 urges sensing pawl Itoward film 14.

A lifting lever 124 is rotatably carried by a stud 126 on housing andhas an abutment 128 which underlies an abutment 130 on arm 112 ofsensing pawl 106. The other end of lifting lever 124 lies in thepath ofgear sector 26.

OPERATION 100 so that film wind lever 22 cannot be moved to the left totransport more film. Referring to FIG. 2, to expose a picture, bodyrelease lever 46 is depressed to rotate shutter release lever 40 in aclockwise direction against the force of spring 48. Tab 102 on theshutter release lever contacts tab 104 on metering lever 96 to raise themetering lever from its active, phantom line position to itsinactive,full line position shown in FIG. 2. With tab 120 raised, spring 118acting on retainer 116 is free to rotate film sensing pawl 106 in acounterclockwise direction to its full line position shown in FIG. 2.Tab 120 of the metering lever is now above the top surface of retainer116 so that metering pawl 98 will not return to ratchet 100 when bodyrelease lever 46 is released to allow counterclockwise rotation ofshutter release lever 40 to its phantom line position.

Referring now to FIG. 3, because metering pawl 98 has been disengagedfrom ratchet 100, film advance lever 22 can now be moved to the left.Such movement rotates gear sector 26 in a counterclockwise direction,causing similar rotation of gear and clockwise rotation of gear 38 andratchet 100. Rotation of gear20 causes film to be wound onto cartridgetake-up roll. it

will be noted that gear sector 26 has been rotated away from contactwith lifting arm 124 to allow spring 122 to move film sensing pawl 106into contact with the film surface.

When the next succeeding film perforation 17, advancing in the directionof arrow 132, reaches the position of sensing pawl 106, the pawl dropsinto the perforation as shown in FIG. 4. The operator continues to moveslide 22 to the left so that the trailing edge of per. foration 17causes clockwise rotation of sensing pawl 106 and retainer 116 to removethe top surface of the retainer from below tab 120 of metering lever 96,thereby allowing the metering lever to be moved by spring 101 to itsfull line position shown in FIG. 5 to deactivate the film windingmechanism and prevent further movement of slide member 22 to the left.The slide member is now moved back to the right by spring 34, and in somoving rotates sector 26 in a clockwise direction until it contactslifting lever 124 and rotates that lever in a counterclockwise directionto lift filmsensing pawl 106 from perforation 17 as shown inFlG. 6. Thecamera elements are now'positioned as shown in FIG. 1 so thatan exposuremay be made.

Since at the time of an exposure, pawl 106 has been removed from thefilm perforation by lifting ratchet 124, the force of spring 118 is nottransmitted to the film. Otherwise, such force might cause film movementin a rightwardly direction at the time of exposure because there isusually some jarring of the camera when the high energy lever isreleased.

The invention has been described in detail with particular reference toa preferred embodiment thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

I claim:

1. In a camera having l a housing including a space i for receiving rollfilm perforated at predetermined me- FIG. I shows the elements of thecamera in their retering intervals, (2) means defining an exposureplane, (3) transport means, including a member mounted on said housingfor movement away from and back to a rest position, for advancingreceived film along said exposure plane, (4) film sensing means, movablebetween a retracted position on one side of said exposure plane and aposition transversing said exposure plane and extending through one ofthe film perforations, for detecting the presence of a perforation at apredetermined position along said exposure plane, and (5) meteringmeans, interconnecting said film sensing means and said transport means,for preventing further film advancement by said transport means whensaid film sensing means detects the presence of a perforation at saidpredetermined position; the improvement comprising means interconnectingsaid member and said film sensing means for returning said film sensingmeans to its retracted position in response to movement of said memberto its rest position.

2. The improvement asdefined in claim 1 further comprising spring meansfor urging said member toward its rest position.

3. The improvement as defined in Claim 2 further comprising spring meansfor urging said film sensing means away from its retracted position.

4. In a camera having (1) a housing including a space for receiving rollfilm perforated at predetermined metering intervals, (2) means definingan exposure plane, (3) transport means including a film wind memberreciprocally mounted on said housing for movement away from a restposition for advancing received film along said exposure lane, 4) ametering mechanism having an active condition for preventing furtherfilm advancement by said transport means and an inactive condition, (5)means for releasably latching said metering mechanism in its inactivecondition, (6) means urging said metering mechanism into its activecondition, (7) a shutter release lever movable from a first position toa second position for effecting exposure of the film at said exposureplane, and (8) means for placing said metering mechanism in its inactivecondition when said shutter release lever is moved to its secondposition; the improvement comprising:

a film sensing pawl movable between a retracted position on one side ofsaid exposure plane and a position transversing said exposure plane andextending through one of said film perforations to detect the presenceof a perforation at a predetermined position;

spring means urging said sensing pawl toward its extended position;

means for releasing said latching means upon movement of said sensingpawl to a predetermining location in its extended position; and

means interconnecting said film wind member and said film sensing pawlfor moving said pawl to its retracted position when said film windmember is moved to its rest position.

5. In combination with a camera's film advancing mechanism whichincludes a film wind member movable toward and away from a stationaryposition, and means for advancing perforated film along an exposureplane when said member is moved away from said stationary position, afilm metering mechanism comprising:

a film sensing pawl movable (l) in first and second opposed directionsbetween a retracted position on one side of said exposure plane and aposition transversing said exposure plane and extending through aperforation in the film, and (2) in third and fourth opposed directionsgenerally parallel to said exposure plane when said sensing pawl is inits extended position;

spring means urging said sensing pawl in its third direction, saidsensing pawl being movable in its fourth direction to a meteringposition by the trailing edge of a film perforation advancing along saidexposure plane;

means interconnecting said sensing pawl and said film advancingmechanism for preventing further film advancement by said film advancingmechanism when said sensing pawl is in its metering position; and

means interconnecting said member and said sensing pawl for moving saidsensing pawl to its retracted position in response to movement of saidmember to its stationary position.

6. In a camera having I. a housing including a space for receiving rollfilm perforated at predetermined metering intervals,

2. means defining an exposure plane,

3. a film sensing pawl movable between a retracted position on one sideof said exposure plane and an extended position transversing saidexposure plane and extending through one of the film perforations todetect the presence of a perforation at a predetermined position, and

4. a film advance mechanism including (a) transport means operable foradvancing received film along said exposure plane and (b) metering meansresponsive to the detection of a perforation at said predeterminedposition by said sensing pawl for pre-venting further film advancementby said transport means; the improvement comprising:

5. means operable for moving said sensing pawl to its retractedposition; and v 6. means responsive, after the sensing of a filmperforation at said predetermined position by said sensing pawl, to afilm advance terminating movement of said film advance mechanism formoving said sensing pawl to its retracted position.

1. In a camera having (1) a housing including a space for receiving rollfilm perforated at predetermined metering intervals, (2) means definingan exposure plane, (3) transport means, including a member mounted onsaid housing for movement away from and back to a rest position, foradvancing received film along said exposure plane, (4) film sensingmeans, movable between a retracted position on one side of said exposureplane and a position transversing said exposure plane and extendingthrough one of the film perforations, for detecting the presence of aperforation at a predetermined position along said exposure plane, and(5) metering means, interconnecting said film sensing means and saidtransport means, for preventing further film advancement by saidtransport means when said film sensing means detects the presence of aperforation at said predetermined position; the improvement comprisingmeans interconnecting said member and said film sensing means forreturning said film sensing means to its retracted position in responseto movement of said member to its rest position.
 2. The improvement asdefined in claim 1 further comprising spring means for urging saidmember toward its rest position.
 2. means defining an exposure plane, 3.a film sensing pawl movable between a retracted position on one side ofsaid exposure plane and an extended position transversing said exposureplane and extending through one of the film perforations to detect thepresence of a perforation at a predetermined position, and
 3. Theimprovement as defined in Claim 2 further comprising spring means forurging said film sensing means away from its retracted position.
 4. In acamera having (1) a housing including a space for receiving roll filmperforated at predetermined metering intervals, (2) means defining anexposure plane, (3) transport means including a film wind memberreciprocally mounted on said housing for movement away from a restposition for advancing received film along said exposure plane, (4) ametering mechanism having an active condition for preventing furtherFilm advancement by said transport means and an inactive condition, (5)means for releasably latching said metering mechanism in its inactivecondition, (6) means urging said metering mechanism into its activecondition, (7) a shutter release lever movable from a first position toa second position for effecting exposure of the film at said exposureplane, and (8) means for placing said metering mechanism in its inactivecondition when said shutter release lever is moved to its secondposition; the improvement comprising: a film sensing pawl movablebetween a retracted position on one side of said exposure plane and aposition transversing said exposure plane and extending through one ofsaid film perforations to detect the presence of a perforation at apredetermined position; spring means urging said sensing pawl toward itsextended position; means for releasing said latching means upon movementof said sensing pawl to a predetermining location in its extendedposition; and means interconnecting said film wind member and said filmsensing pawl for moving said pawl to its retracted position when saidfilm wind member is moved to its rest position.
 4. a film advancemechanism including (a) transport means operable for advancing receivedfilm along said exposure plane and (b) metering means responsive to thedetection of a perforation at said predetermined position by saidsensing pawl for pre-venting further film advancement by said transportmeans; the improvement comprising:
 5. In combination with a camera''sfilm advancing mechanism which includes a film wind member movabletoward and away from a stationary position, and means for advancingperforated film along an exposure plane when said member is moved awayfrom said stationary position, a film metering mechanism comprising: afilm sensing pawl movable (1) in first and second opposed directionsbetween a retracted position on one side of said exposure plane and aposition transversing said exposure plane and extending through aperforation in the film, and (2) in third and fourth opposed directionsgenerally parallel to said exposure plane when said sensing pawl is inits extended position; spring means urging said sensing pawl in itsthird direction, said sensing pawl being movable in its fourth directionto a metering position by the trailing edge of a film perforationadvancing along said exposure plane; means interconnecting said sensingpawl and said film advancing mechanism for preventing further filmadvancement by said film advancing mechanism when said sensing pawl isin its metering position; and means interconnecting said member and saidsensing pawl for moving said sensing pawl to its retracted position inresponse to movement of said member to its stationary position.
 5. meansoperable for moving said sensing pawl to its retracted position; and 6.In a camera having
 6. means responsive, after the sensing of a filmperforation at said predetermined position by said sensing pawl, to afilm advance terminating movement of said film advance mechanism formoving said sensing pawl to its retracted position.